1.0 Field of the Invention
My invention relates generally to transferring data from a server to a subscriber device via the Public Switched Telephone Network (PSTN). More particularly, my invention relates to methods and systems for transferring data from a server to a subscriber device via the PSTN without establishing a call between the server and subscriber device and without the PSTN switching components having inherent knowledge as to the data content.
2.0 Description of the Background
The rise of alternate forms of communication and the ever present need for public safety are several trends fueling the need for a large-scale data distribution capability that can provide timely and efficient delivery of information to residential subscribers. With respect to alternate forms of communication, many business subscribers have the benefit of dedicated Internet access and typically carry a wireless device. As a result, they have the ability to receive timely/instantaneous notification of new awaiting email and network-based faxes, and can be paged and receive short text messages via wireless communications. Dedicated Internet access also allows content providers and advertisers to push information, such as stock quotes and targeted marketing information, to these subscribers via emerging “push-information technologies.”
However, unlike business subscribers, typical residential subscribers do not have dedicated Internet access and usually do not carry wireless devices. As a result, convenient and timely methods for notifying these subscribers of pending email and fax information or to automatically “push” new forms of information into their homes do not exist unless these subscribers first physically access their Internet service providers. Similarly, Convergent Services (e.g., Unified Messaging) have emerged that combine the capabilities of both the PSTN and Internet and provide subscribers with a unique mix of voice and data services. However, again, subscribers must physically access a server to determine if there is pending information.
Public safety has also created a need for information distribution to the residential subscriber. Existing public alerting methods, such as community sirens that are external to the home, are proving to be insufficient and in some cases ineffective as the population grows and settles in new remote areas. As a result, there is a need for public warning and emergency alerting systems resident within the home that can alert a given population as to the onset of severe weather or flood, the need to evacuate, a missing child, water contamination, potential industrial hazard, etc.
Needs like those presented above can be effectively satisfied through a data-oriented message distribution system that can send “data” from a “central server” to a subscriber device. Such “data” could be a short text message providing a public warning, Internet-based advertisement/stock quotes, or a page-like message. The data could also alert subscribers of pending information and prompt them for information retrieval.
Although tomorrow's “Next Generation Networks” provide great flexibility for data transport that could meet these emerging subscriber needs, these solutions lack widespread ubiquitous deployment today. In contrast, the current PSTN has nearly ubiquitous deployment and continues to host a large volume of subscribers. Consequently, a solution that could deliver data messages to subscribers based on today's PSTN has tremendous value and potential because it would not require the need to deploy a second data network. A conceptual diagram of such a system is shown in FIG. 1. Central server 102 aims to deliver and exchange data/voice information with a plurality of subscriber CPE devices, 106, through PSTN infrastructure 104.
Although the PSTN offers ubiquitous access, there are several reasons as to why it is not an ideal network to implement data-oriented network messaging capabilities. First, the PSTN has been traditionally optimized to transport and switch telephone voice traffic and is therefore characterized by fixed bandwidth, making it non-ideal for data transport. Second, because the PSTN is designed around the central concept of a telephone call, two endpoints cannot communicate with one another without first establishing a switched connection. Call connection establishment is slow and ties up switch and network resources making the network inefficient for large-scale distribution of data, especially for broadcast types of applications where time is critical (e.g., as would be needed by alerting systems). In addition, call connection establishment does not effectively meet the subscriber needs presented above. To be effective, the delivery of data messages needs to occur without requiring subscriber interaction and irrespective of whether the subscriber line is idle or in use. Ideally, a solution based on the PSTN should only utilize the PSTN's connectivity infrastructure to deliver data message from the central server to the subscriber-based CPE devices.
Another issue with the PSTN is that service applications traditionally must be deployed within the internal PSTN switching components and require the switching components have specific knowledge of the application in at least two ways: (1) the means by which a terminating switch must establish a connection to a subscriber device and deliver data to this device, and (2) the data formats used by the service application to transport information through the network. As a result, service applications and switching components are tied together and a given service application cannot readily support other types of services without modifying the application. Hence, each time a new service is deployed, the PSTN switching components must be re-programmed, which is both costly and time consuming. As will be presented below, my invention overcomes this limitation by defining a generic framework within the PSTN infrastructure that can support numerous services thereby severing the overriding application from the PSTN infrastructure. As a result, service application development and deployment are performed on the network endpoints (i.e., a central server and CPE devices), which are less costly and time consuming to enhance. These service applications then utilize the generic framework of my invention without modifying the switching components.
3.0 Prior Art Systems
Prior art systems have been developed that allow a central server (central server will be used generically in the description of the prior art systems) to send data to a subscriber CPE device through the PSTN. However, in addition to the concerns mentioned above related to bandwidth limitations, call-establishment delays, and application deployment, these systems do not address issues related to Local Number Portability (LNP) and do not provide a cost-effective and timely way to broadcast information to numerous subscribers. As a result, these systems do not adequately address the emerging and changing needs of today's residential subscriber.
In U.S. Pat. Nos. 5,189,694 and 5,394,461, Stuart Garland teaches a system, as shown in FIG. 2, whereby central server 202 has a dedicated direct “Utility Telemetry Trunk” (UTT) connections, 204–208, through the PSTN to each of a plurality of Stored Program Control Systems (SPCS) 210–214, serving desired CPE devices, 216–220. (Note that Garland utilizes a “central office service unit” and “utility controller” that can be collectively treated as a central server for the purposes of this discussion.) However, Garland's implementation posses several drawbacks with respect to the delivery of data messages through the PSTN.
First, the system is not a true network-based solution and therefore does not efficiently provide ubiquitous access to all subscribers. Central server 202 requires a UTT trunk to a given SPCS before it can communicate with the CPE served by that SPCS. Hence, the solution does not cost effectively scale to serve all CPE in a network.
Second, to address LNP related issues, the central server requires a UTT connection to every service provider/SPCS that may serve a given subscriber. If there is no UTT connection, the subscriber cannot be reached. In addition, the central server requires a database to keep track of ported subscribers.
Third, the solution does not provide for efficient data transfer. All communications between a central server and CPE device require a switched voice connection be established through a UTT and the switching matrix of a SPCS. Voice connections are time-consuming to establish and are inherently slow for the transmission of data. In addition, during broadcast scenarios, numerous voice connections can create switch congestion and therefore call blocking.
Fourth, the solution does not provide a cost-effective broadcast solution, as would be needed, for example, by an emergency alerting application. Garland does describe a two-phase broadcast capability whereby a central server first delivers pre-determined broadcast-instructions (including a broadcast list of numbers) to a SPCS. The central server then delivers to the SPCS in a second message the data to be broadcast. However, this solution is again hindered by the fact that large-scale broadcast requires the central server have a UTT trunk to every switch. Another issue is that due to the speed of the UTT trunk, it is time consuming to dynamically download new broadcast lists, a feature that is required for delivering natural disaster information.
Advantageously, Garland's system has a mechanism for severing an overriding service application from the PSTN switching components, but this mechanism has limitations. Specifically, Garland defines a control mechanism by which the central server can choose from one of several predefined transport services, whereby a transport service instructs the SPCS on how to establish the connection to the CPE and how to transport data to the CPE over the access loop. However, because Garland's system utilizes a “GR-30-CORE” interface (as defined in GR-30-CORE LSSGR Voiceband Data Transmission Interface, Section 6.6, by Telcordia Technologies, Inc.) between the SPCS and CPE, each transport service has a predefined data format for transmission. Hence, the transport services are inherently based on certain types of service applications and as a result, there is an inherent limitation as to the types of applications that can be implemented on this system without the continuous definition of new transport services. New transport services require re-programming of the PSTN switching components.
Nortel Networks, Inc. describes in functional feature document, Suppressed Ringing Access, a system for establishing a suppressed ringing access call connection between a central server and a subscriber device through the use of a modified version of Integrated Services Digital Network (ISDN) call setup (ISDN and CCS/SS7 call establishment do not support signaling for suppressed ringing access). Under this system, a central server places a call to a service activating directory number/application on the terminating SPCS that serves the subscriber. The SPCS-based application then completes the suppressed ringing access connection to the subscriber. Because the system utilizes ISDN call setup procedures, there is no need for dedicated trunks, as is the case with Garland, thereby making the system ubiquitous and scalable (i.e., the call connection is switched through the network). However, the system still poses several drawbacks making it non-ideal for data message transport.
First, similar to Garland, the transmission of data between the central server and CPE device utilizes a switch-based voice connection. This connection is time consuming to establish, especially when having to make numerous connections such as for broadcast applications.
Second, the system has LNP related issues for ported subscribers because the central server places the call to a switched-based application on the SPCS rather than directly to the subscriber. Hence, the call establishment procedures do not inherently resolve the subscriber's number and re-route the call. To solve this LNP issue, the SPCS would need to maintain a local database of ported numbers, which is costly.
Third, the application is inherently tied to the PSTN switching components and therefore lacks flexibility to support other applications. Unlike Garland, the system does not define a control mechanism between the central server and terminating SPCS whereby the server can instruct the SPCS on how to establish the connection to the CPE device. Call establishment procedures are hardcoded in the SPCS based application.
Lastly, the system only supports subscriber broadcast by sending individual messages to each subscriber, which is inefficient.
Telcordia Technologies, Inc. defined a message waiting notification service in, TR-NWT-1401: LSSGR Visual Message Waiting Indicator, and GR-866-CORE: ISDN Message Service Generic Switching and Signaling Requirements, as shown in FIG. 3. Under this service, network-based voicemail system 302 (the central server for the purposes of this discussion) records voice messages for a subscriber. System 302 then notifies the subscriber that new voice messages are waiting by activating an indicator on subscriber CPE device 316 as follows. Voicemail system 302 sends a message, describing the subscriber's incoming call history, to originating SPCS 306 over access link 304, which is either an ISDN/Message Desk Interface (MDI) or a Simplified Message Desk Interface (SMDI). Originating SPCS 306 in turn notifies terminating SPCS 312 of the call history by launching a “Transaction Capabilities Application Part” (TCAP) query over CCS network 308. SPCS 312 then notifies CPE device 316 of the call history by sending a message over access link 314 using either a GR-30-CORE predefined message or through ISDN non-call associated signaling.
Because this solution utilizes the CCS/SS7 network, it advantageously supports the delivery of data from a central server to a subscriber without the need to establish a voice connection. It also addresses ported numbers. However, this system has several drawbacks making it non-ideal for data message transport.
First, the solution is tailored towards a specific application (voicemail notification) and is therefore not adaptable to applications requiring other forms of message transfer. Specifically, the protocols defined for transporting data from the voicemail system to the originating SPCS, between the originating and terminating SPCS's, and from the terminating SPCS to the CPE device are specific to the transport of voicemail information and are not adaptable to the transport of any data (i.e., the data content is limited in both size and type). In addition, the system does not define a mechanism for the central server to instruct the terminating SPCS on how to establish the connection from the terminating SPCS to the CPE device. Both issues prevent the system from supporting service applications other than voicemail without modification to the PSTN switching components.
Second, the solution does not support a broadcast mechanism from the central server to a plurality of subscribers. The central server could broadcast a message, one-at-a-time to numerous subscribers, but this is time-consuming and could potentially create congestion within the CCS/SS7 network.
Telcordia Technologies, Inc. also defined an AIN function, called the “Create-Call” function, in GR-1298-CORE: AINGR: Switching Systems. This function permits a Service Control Point (SCP) to request that a switch establish a call on behalf of a subscriber CPE device. Specifically, through this function the SCP can instruct a switch to first alert a CPE device and then establish a call to a central server (e.g., an Intelligent Peripheral) from this device. Unlike the systems described above, here the call is originated from the subscriber rather than from the central server. One application of this function is to setup an unattended call between an Intelligent Peripheral and an ADSI screen-phone to download service scripts.
The Create-Call function poses several drawbacks making it non-ideal for data message transport. First, the function does not support efficient broadcast from a central server since call origination occurs from the CPE device to the central server. Second, the function does not provide for efficient data transfer since all communications between a central server and CPE device require a switched voice connection. Third, the function is limited with respect to the types of data that can be sent to a CPE device.